During warm up of an internal combustion engine, the engine block structure acts as a large heat sink because the thermal inertia of the engine block structure is an order of magnitude greater than the coolant and oil. For this reason, the engine block structure may take longer to warm up than the oil. By way of example, hot oil returning from a piston cooling gallery, which has been heated by combustion events, may hit a crank of the engine and the oil may be thrown against the cooler crankcase. When oil is thrown against the crankcase wall, the oil may lose heat due to the large thermal inertia and large surface area of the crankcase. Similarly, oil returning from the cylinder head has been heated and may lose heat upon returning through the engine block to the oil sump. The resulting colder oil has a higher viscosity, which may lead to higher frictional losses, and in turn, higher fuel consumption and/or a reduced cabin heating.
Exemplary oil pans and windage trays are known whose inclusion in an engine block acts as a barrier between a wet sump area of the engine and the crankshaft. Such apparatuses may act to reduce the amount of windage or aeration of the oil within the engine. However, previous examples locate the tray between the crankshaft of the engine and the sump. For example, US2012/0067319, WO2013/083765, and US2009/0277416 describe apparatuses configured for placement below the crankshaft. U.S. Pat. No. 7,341,039 alternatively describes an engine with a tilted in-line configuration, and accordingly locates the windage tray between the sump and the connecting rod coupling to the piston. US2004/0177826 describes windage tray with an inverted arrangement. However, the disclosed apparatus is designed to block air and oil turbulence caused by the rotating crankshaft, and the apparatus shown is also configured for placement beneath a connecting rod that couples a piston to the crankshaft. The systems above, thus, lack an ability to reduce thermal losses due contact interactions between oil and the engine block structure. Specifically, heated engine oil may still hit an engine crank and even be thrown against the crankcase wall, which leads to higher frictional losses, and increases the duration of time for oil heating in some instances.
The inventors have recognized issues with such approaches and herein describe a crankcase oil catcher configured for placement above a crankshaft and below a piston of an engine. In particular, the crankcase oil catcher comprises one or more contoured surfaces for catching dispersed oil in the crankcase and directing the dispersed oil along the one or more contoured surfaces of the crankcase oil catcher to a crank sump. Advantageously, the crankcase oil catcher includes a first aperture for a connecting rod of the crankshaft to pass through. In this way, the technical result is achieved that dispersed oil within the crankcase can be caught by the crankcase oil catcher and directed to the sump without experiencing thermal losses due to contact with the engine structure.
In one disclosed example, the crankcase oil catcher is configured for placement above a crankshaft and below a piston while a top surface of the crankcase oil catcher has a contour further configured to follow a contour of a crankcase wall while maintaining a substantially constant spacing therefrom. In this way, the top surface allows dispersed oil in the engine crankcase to be caught and directed to a crank sump along the top surface of the crankcase oil catcher while preventing oil from contacting the crankcase casing wall. Further inclusion of an aperture whose width is smaller than a width of the piston associated with a connecting rod of the engine crankshaft then allows for providing the crankcase oil catcher beneath an engine cylinder, and thus for increasing the amount of oil caught therefrom. As described in greater detail below, the aperture is sized only for passage of the crankshaft. Additional structural features like a lip protruding in a direction of the piston extending around a perimeter of the aperture further prevent oil on the top surface from falling through the aperture.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings. It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.